I have already created a mini backgammon set with impressive features: easy portability, robust design, and a strong clasp. The dimensions are 126.2 mm x 78 mm when closed, and I've increased the thickness for durability. The included 2.8 mm diameter pin can be substituted with a metal pin to enhance strength.

If you intend to scale up the design, keep the following points in mind:

Maintain Proportions: When scaling up, ensure that you maintain the original proportions. This will help preserve the overall aesthetic and gameplay experience.

Gap and Pin Size: Pay attention to the gaps and the size of the pins when scaling. Enlarging the design may require adjusting these aspects to ensure smooth assembly and functionality.

Material Selection: As you intend to use a metal pin for added strength, consider using appropriate materials for the entire set to maintain its sturdiness during use.

Testing and Assistance: Before finalizing the scaled-up design, perform test prints and assemblies to identify any issues and optimize the design further. Feel free to reach out for assistance if needed.

Keep in mind that the optimal scale-up factor will depend on the specifics of your design and manufacturing process.you can see some pictures from what I 3d printed here